@article{WinartoSutterTockhornetal., author = {Winarto, Hanifah and Sutter, Johannes and Tockhorn, Philipp and Škorjanc, Viktor and Patil, Pramila and Berwig, Sebastian and Zimmermann, Lea and Mart{\´i}nez-Denegri, Guillermo and Albrecht, Steve and Becker, Christiane}, title = {Periodic Inverted Micropyramids for Optically Optimized Fully Textured Solution-Processed Perovskite Solar Cells}, series = {Solar RRL}, volume = {9}, journal = {Solar RRL}, number = {23}, publisher = {Wiley}, issn = {2367-198X}, doi = {10.1002/solr.202500613}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-22175}, pages = {10}, abstract = {Optical performance of perovskite-based solar cells can be enhanced by utilizing fully textured interfaces. However, solution processing of perovskite films on textured surfaces is a nonstraightforward and challenging process, particularly if optically most efficient micrometer-sized textures are used. In this work, we present fully textured solution-processed perovskite solar cells on periodic inverted micropyramids. The textures have a period of 4 μm with varying pyramid depths and are fabricated by wet-chemical etching of silicon with subsequent replication on glass substrates using nanoimprint lithography. Inverted pyramids are shown to enable low reflectance similar to random micropyramids on silicon. Additionally, they are able to confine perovskite precursor solution within its structure during spin coating, resulting in a conformal, fully textured perovskite film. We demonstrate that the resulting fully textured single-junction perovskite solar cells feature a reduced reflection loss of up to 1.2 mA/cm 2 in short-circuit current density. Moreover, we observe that the amount of lead iodide in the perovskite precursor solution crucially impacts growth and nonradiative recombination losses of the fully textured perovskite solar cells on inverted micropyramids. Finally, we prove the versatility of our approach by also demonstrating conformal coating with slot-die coating, which is a scalable process considered for industrial application.}, subject = {Solar cells}, language = {en} } @article{Farias‐BasultoKafedjiskaBertrametal., author = {Farias-Basulto, Guillermo and Kafedjiska, Ivona and Bertram, Tobias and Riedel, Maximilian and Emery, Quiterie and Remec, Marko and Graniero, Paolo and Khenkin, Mark and Kaufmann, Christian A. and Lauermann, Iver and Klenk, Reiner and Schlatmann, Rutger and Ulbrich, Carolin}, title = {Perovskite-CIGSe Tandem Solar Cell: Over One Year of Outdoor Monitoring}, series = {Advanced Energy and Sustainability Research}, volume = {6}, journal = {Advanced Energy and Sustainability Research}, number = {12}, issn = {2699-9412}, doi = {10.1002/aesr.202500162}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-22159}, pages = {11}, abstract = {Tandem solar cells can surpass the limitations of single-junction devices, promising increased performance due to lower thermalization losses. Even though many research and industrial upscaling efforts are based on perovskite-Si tandems, all-thin-film photovoltaic (PV) devices, for instance with chalcopyrite (CIGSe) and perovskite, can offer many advantages such as significant cost and material savings and access to niche markets like building integrated- and flexible PV. However, long-term stability and outdoor performance of perovskite-based tandem devices is to this day challenging. This work presents the first data analysis of year-round outdoor measurements (mpp-tracked) of a perovskite-chalcopyrite tandem device with a starting efficiency of about 23.14\% before encapsulation. The maximum outdoor performance of the tandem device changed during the period of observation, reaching the peak performance in April and then decreased due to the device degradation. At its maximum outdoor performance, the tandem could reach up to 68\% higher instantaneous power output, relative to its single-junction reference (CIGSe-SJ). In addition, a quantitative time series performance analysis, exemplary qualitative imaging characterization of the tandem before and after outdoor exposure, is shown. Finally, the possibility of predicting the immediate performance of an all-thin-film tandem is verified by using a multiple linear regression model with accuracies generally exceeding 90\%.}, subject = {Machine learning}, language = {en} } @article{FariasBasultoMehlhopOttoetal., author = {Farias-Basulto, Guillermo and Mehlhop, Thede and Otto, Nicolas J. and Bertram, Tobias and Jäger, Klaus and Gall, Stefan and Weinberger, Nikolaus and Schlatmann, Rutger and Lauermann, Iver and Klenk, Reiner and List-Kratochvil, Emil and Kaufmann, Christian A.}, title = {Improving Perovskite/CIGS Tandem Solar Cells for Higher Power Conversion Efficiency through Light Management and Bandgap Engineering}, series = {ACS Applied Materials \& Interfaces}, volume = {17}, journal = {ACS Applied Materials \& Interfaces}, number = {40}, publisher = {American Chemical Society}, issn = {1944-8244}, doi = {10.1021/acsami.5c15458}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-21725}, pages = {56250 -- 56255}, abstract = {Perovskite and chalcopyrite materials are excellent absorbers for highly efficient, all-thin-film tandem solar cells. This work presents a certified world record for such a device, achieving a power conversion efficiency of 24.6 ± 1.1\% under steady-state conditions. The best IV parameters extracted from certified current-voltage measurements presented a short-circuit current density of around 19.3 mA/cm 2 , an open-circuit voltage of 1.765 V, and a fill factor of 71.8\%. In comparison to our previous record, the current density improved considerably, mainly due to the lowering of the bandgap of the bottom subcell and the improved optics of the top perovskite cell.}, subject = {Photovoltaic}, language = {en} } @article{SchultzFenskeOttoetal., author = {Schultz, Christof and Fenske, Markus and Otto, Nicolas and Dion-Bertrand, Laura-Isabelle and G{\´e}linas, Guillaume and Marcet, St{\´e}phane and Dagar, Janardan and Schlatmann, Rutger and Unger, Eva and Stegemann, Bert}, title = {Loss Analysis of P3 Laser Patterning of Perovskite Solar Cells via Hyperspectral Photoluminescence Imaging}, series = {Solar}, volume = {5}, journal = {Solar}, number = {2}, editor = {Boucl{\´e}, Johann}, publisher = {MDPI}, issn = {2673-9941}, doi = {10.3390/solar5020013}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-20545}, abstract = {Upscaling perovskite solar cells and modules requires precise laser patterning for series interconnection and spatial characterization of cell parameters to understand laser-material interactions and their impact on performance. This study investigates the use of nanosecond (ns) and picosecond (ps) laser pulses at varying fluences for the P3 patterning step of perovskite solar cells. Hyperspectral photoluminescence (PL) imaging was employed to map key parameters such as optical bandgap energy, Urbach energy, and shunt resistance. The mappings were correlated with electrical measurements, revealing that both ns and ps lasers can be utilized for effective series interconnections with minimal performance losses at optimized fluences. Our findings provide a deeper understanding of fluence-dependent effects in P3 patterning. Moreover, the results demonstrate that the process window is robust, allowing for reasonable cell performance even with deviations from optimal parameters. This robustness, coupled with the scalability of the laser patterning process, emphasize its suitability for industrial module production.}, subject = {Photoluminescence}, language = {en} }